Accessing Quinoxalines by Ring-Opening/Cyclization/Detosylation/Aromatization of Activated Aziridines with 2-Bromoanilines: Synthesis of Tyrphostin AG 1296

Abstract

2‐Arylquinoxalines have been synthesized by an unprecedented CuI‐catalyzed ring‐opening/cyclization/detosylation/aromatization cascade reaction of activated aziridines with 2‐bromoanilines. The regioselective, high‐yielding transformation is amenable to a variety of aziridines and 2‐bromoanilines. Tyrphostin AG 1296, a PDGF‐receptor tyrosine kinase inhibitor, has also been synthesized. Substituted 2‐arylquinoxalines have been synthesized by an unprecedented CuI‐catalyzed ring‐opening/cyclization reaction followed by detosylation/aromatization of activated aziridines with 2‐bromoanilines. The transformation efficiently accommodates a wide range of aziridines and 2‐bromoanilines to afford the desired quinoxaline frameworks in excellent yields (up to 86 %) as single regioisomers. The methodology has also been conveniently applied to the synthesis of tyrphostin AG 1296, a PDGF‐receptor tyrosine kinase inhibitor.